THERMODYNAMICS 101

One of the core innovations of the SustainX technology is the use of isothermal, as opposed to adiabatic, gas cycling. An adiabatic process is one that does not exchange heat with its surrounding environment. Without heat transfer, a gas will increase in temperature as it is compressed; and as it gets hotter, it tends to resist further compression (i.e., each increment of compression must be performed on a volume of gas that is at higher pressure than if it had not been heated by prior compression). While undergoing adiabatic expansion (such as is used in classical CAES) the gas cools, resulting in a second inefficiency; at each increment of expansion, the gas is at lower pressure than if it had not been cooled by prior expansion, and so can do less useful work.